Table of Revisions

ion Refinement Abstraction refinement [7] is a process, in which a model is first grossly abstracted, to form a much smaller (and easier to verify) model, and then iteratively refined. At each iteration, a model checker checks the current abstract model. If it can come up with a definite answer (either pass or fail), the process terminates. Otherwise, a refined model is built for the next iteration. The abstract models are constructed such that a proof by the model checker will also hold on the concrete model. A falsification, on the other hand, must be checked on the concrete model to determine its validity. This however may be easier than model checking the concrete model, as we only have to check whether a falsifying counterexample is also valid on the concrete model. Whenever a counterexample is found to be spurious (cannot be reconstructed on the concrete model) a refinement process takes place, yielding a less abstract model. The whole abstraction refinement process is demonstrated in Figure 2.ion refinement [7] is a process, in which a model is first grossly abstracted, to form a much smaller (and easier to verify) model, and then iteratively refined. At each iteration, a model checker checks the current abstract model. If it can come up with a definite answer (either pass or fail), the process terminates. Otherwise, a refined model is built for the next iteration. The abstract models are constructed such that a proof by the model checker will also hold on the concrete model. A falsification, on the other hand, must be checked on the concrete model to determine its validity. This however may be easier than model checking the concrete model, as we only have to check whether a falsifying counterexample is also valid on the concrete model. Whenever a counterexample is found to be spurious (cannot be reconstructed on the concrete model) a refinement process takes place, yielding a less abstract model. The whole abstraction refinement process is demonstrated in Figure 2. Figure 2: Abstraction refinement Localize Verify Concrete model Abstract model Refined model Refine Reconstruct Failed Real bug